Analysis of information sources in references of the Wikipedia article "Janka hardness test" in English language version.
{{cite journal}}: Cite journal requires |journal= (help) The record softness of 22 lbf is often falsely ascribed to quipo, but all such reports appear to be a misreading of figures 15 and 16 from this primary source, which makes clear that measurement is of balsa, and the softest quipo measured was 46 lbf tangential, 38 lbf radial.